Radio Frequency Identification (RFID) is utilized in a variety of applications with RFID readers interrogating RFID tags for purposes of identification, location, tracking, and the like. However, a single RFID reader in a large room will not be able to read all the RFID tags at opposite ends of the room. Therefore, in an exemplary RFID application, a plurality of RFID readers are mounted overhead (e.g., ceiling mounted) in a grid array to be able to read all the RFID tags, such as in a retail environment, a factory environment, a warehouse environment, etc. However, having multiple RFID readers in close proximity has disadvantages.
For example, interference can be experienced between RFID readers which have active antennas aligned with each other. This interference can cause both readers to not see tags of interest, which are important for tracking inventory accurately. In addition, if the RFID readers are allowed to run un-synchronized, the antennas of nearby readers may align and interfere with each other causing a reduction of tag reads. This would compromise the accuracy of the system as tags of interest may not be seen at the moment of availability. This same issue is also a problem for channel frequency across the operating band. In the United States, the RFID operating band has fifty channels, while in the European Union there are only four channels. Testing with four channels identified that when two nearby readers try to read one tag on the same frequency or even adjacent frequencies the tag could not be read. Therefore, it is equally important to manage channel frequencies, antenna alignment, and synchronization.
Accordingly, there is a need for an RFID system and method that overcome the aforementioned limitations.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.